From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
To: Doug Smythies <dsmythies@telus.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <len.brown@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH] cpufreq: intel_pstate: Override parameters if HWP forced by BIOS
Date: Thu, 09 Sep 2021 07:52:54 -0700 [thread overview]
Message-ID: <9586d66802138dc144836b310ef5b20394c59695.camel@linux.intel.com> (raw)
In-Reply-To: <CAAYoRsVX76Ey9FHhZXdwKWiMdmf0Oi6SKrP2J=XnNgB92sZW1A@mail.gmail.com>
On Thu, 2021-09-09 at 06:30 -0700, Doug Smythies wrote:
> On Wed, Sep 8, 2021 at 11:33 PM Srinivas Pandruvada
> <srinivas.pandruvada@linux.intel.com> wrote:
> >
> > On Wed, 2021-09-08 at 20:48 -0700, Doug Smythies wrote:
> > > If HWP has been already been enabled by BIOS, it may be
> > > necessary to override some kernel command line parameters.
> > > Once it has been enabled it requires a reset to be disabled.
> > >
> > > Signed-off-by: Doug Smythies <dsmythies@telus.net>
> > > ---
> > > drivers/cpufreq/intel_pstate.c | 22 ++++++++++++++++------
> > > 1 file changed, 16 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/cpufreq/intel_pstate.c
> > > b/drivers/cpufreq/intel_pstate.c
> > > index bb4549959b11..073bae5d4498 100644
> > > --- a/drivers/cpufreq/intel_pstate.c
> > > +++ b/drivers/cpufreq/intel_pstate.c
> > > @@ -3267,7 +3267,7 @@ static int __init intel_pstate_init(void)
> > > */
> > > if ((!no_hwp &&
> > > boot_cpu_has(X86_FEATURE_HWP_EPP)) ||
> > > intel_pstate_hwp_is_enabled()) {
> > > - hwp_active++;
> > > + hwp_active = 1;
> > Why this change?
>
> It was just to keep it at 1, but I agree not absolutely needed.
>
> >
> > > hwp_mode_bdw = id->driver_data;
> > > intel_pstate.attr = hwp_cpufreq_attrs;
> > > intel_cpufreq.attr = hwp_cpufreq_attrs;
> > > @@ -3347,17 +3347,27 @@ device_initcall(intel_pstate_init);
> > >
> > > static int __init intel_pstate_setup(char *str)
> > > {
> > > + /*
> > > + * If BIOS is forcing HWP, then parameter
> > > + * overrides might be needed. Only print
> > > + * the message once, and regardless of
> > > + * any overrides.
> > > + */
> > > + if(!hwp_active
> > This part of code is from early_param, Is it possible that
> > hwp_active is not 0?
>
> Not at this point, in any testing I did.
> But I do not know the authoritative answer
> to your question.
>
But as you explained you want to prevent repeated print of
"HWP enabled by BIOS". So you need this.
> >
> > > && boot_cpu_has(X86_FEATURE_HWP))
> > > + if(intel_pstate_hwp_is_enabled()){
> > > + pr_info("HWP enabled by BIOS\n");
> > > + hwp_active = 1;
> > > + }
> > > if (!str)
> > > return -EINVAL;
> > >
> > > - if (!strcmp(str, "disable"))
> > > + if (!strcmp(str, "disable") && !hwp_active)
> > > no_load = 1;
> > > - else if (!strcmp(str, "active"))
> > > + if (!strcmp(str, "active"))
> > > default_driver = &intel_pstate;
> > > - else if (!strcmp(str, "passive"))
> > > + if (!strcmp(str, "passive"))
> > > default_driver = &intel_cpufreq;
> >
> > Why "else if" changed to "if" ?
>
> Because it doesn't matter anyway and I would
> have had to figure out another qualifier.
> This way, and given that this executes once per
> intel_pstate command line parameter, the code
> executes the way it used to, overall.
If someone specified intel_pstate=active, it will also compare with
"passive" with this change.
Thanks,
Srinivas
>
> >
> >
> > Thanks,
> > Srinivas
> >
> > > -
> > > - if (!strcmp(str, "no_hwp")) {
> > > + if (!strcmp(str, "no_hwp") && !hwp_active) {
> > > pr_info("HWP disabled\n");
> > > no_hwp = 1;
> > > }
> >
> >
next prev parent reply other threads:[~2021-09-09 14:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 3:48 [PATCH] cpufreq: intel_pstate: Override parameters if HWP forced by BIOS Doug Smythies
2021-09-09 6:33 ` Srinivas Pandruvada
2021-09-09 11:18 ` Rafael J. Wysocki
2021-09-09 13:20 ` Doug Smythies
2021-09-09 16:12 ` Rafael J. Wysocki
2021-09-09 17:22 ` Rafael J. Wysocki
2021-09-10 3:14 ` Doug Smythies
2021-09-10 11:18 ` Rafael J. Wysocki
2021-09-10 15:34 ` Doug Smythies
2021-09-10 15:45 ` Rafael J. Wysocki
2021-09-09 13:30 ` Doug Smythies
2021-09-09 14:52 ` Srinivas Pandruvada [this message]
2021-09-10 4:11 ` Doug Smythies
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